San Francisco, officially the City and County of San Francisco, is the fourth most populous city in California and the 12th most populous city in the United States. It encompasses a land area of 46.7 square miles (121 km2). It is the most densely settled large city in the state of California and the second-most densely populated large city in the United States. San Francisco is the financial, cultural, and transportation center of the San Francisco Bay Area, a region of more than 7.4 million people which includes San Jose and Oakland.